What is meant by Critical angle?

Here are the answers to the questions: Section I - Short Answer Questions (First set): 1. What is meant by simple harmonic motion? Simple harmonic motion (SHM)* is a special type of periodic motion where the restoring force is directly proportional to the displacement from the equilibrium position and acts in the opposite direction. It is characterized by a constant period and amplitude. 2. Differentiate between longitudinal waves and transverse waves. In longitudinal waves*, the particles of the medium vibrate parallel to the direction of wave propagation. Sound waves are an example. In transverse waves*, the particles of the medium vibrate perpendicular to the direction of wave propagation. Light waves and waves on a string are examples. 3. Prove the relation between velocity, frequency and wavelength. The velocity (v) of a wave is the distance it travels per unit time. The wavelength () is the distance covered by one complete wave cycle. The frequency (f) is the number of wave cycles passing a point per unit time. In one time period (T), a wave travels one wavelength (). Therefore, velocity v = distancetime = ()/(T). Since frequency f = (1)/(T), we can substitute this into the equation: v = × (1)/(T) v = f Thus, the relation between velocity, frequency, and wavelength is v = f. 4. Define Electrostatics. Electrostatics* is the branch of physics that deals with the study of electric charges at rest and the phenomena associated with them, such as electric fields, electric potential, and electric forces. 5. Define electric potential and write its unit. Electric potential* at a point in an electric field is defined as the amount of work done per unit positive charge in bringing the charge from infinity to that point without acceleration. Its SI unit is the volt (V)*, which is equivalent to joules per coulomb (J/C). 6. Define capacitor and write its any two types. A capacitor* is an electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by a dielectric material. Two types of capacitors are: • Parallel plate capacitor • Cylindrical capacitor (or electrolytic capacitor, ceramic capacitor, etc.) 7. What is meant by thermionic emission? Thermionic emission* is the process by which electrons are emitted from a heated metal surface. When a metal is heated to a sufficiently high temperature, the thermal energy imparted to the free electrons in the metal becomes enough to overcome the work function (binding energy) of the metal, allowing them to escape. 8. Draw the truth table of OR operation. The OR operation (represented by +) produces an output of 1 if at least one of its inputs is 1. |c|c|c| A & B & X = A+B \\ 0 & 0 & 0 \\ 0 & 1 & 1 \\ 1 & 0 & 1 \\ 1 & 1 & 1 \\ Section I - Short Answer Questions (Second set): 1. What is difference between frequency and Pitch? Frequency* is an objective physical property of a sound wave, defined as the number of complete oscillations or cycles per second, measured in Hertz (Hz). Pitch* is the subjective perception of the frequency of a sound by the human ear. A higher frequency corresponds to a higher perceived pitch, and a lower frequency corresponds to a lower perceived pitch. 2. What is meant by quality of sound? Give an example. The quality (or timbre)* of sound is the characteristic that allows us to distinguish between two sounds of the same pitch and loudness produced by different sources. It depends on the number and relative intensity of overtones (harmonics) present in the sound. Example:* The sound of a piano and a flute playing the same note (same pitch) at the same loudness can be distinguished due to their different qualities. 3. Write the equation to find the speed of sound and write to what factors its speed depend? The general equation to find the speed of sound (or any wave) is: v = f where v is the speed, f is the frequency, and is the wavelength. The speed of sound primarily depends on the following factors: • Nature of the medium: Sound travels fastest in solids, slower in liquids, and slowest in gases. • Temperature: The speed of sound increases with increasing temperature of the medium. • Humidity: In gases, the speed of sound slightly increases with increasing humidity. 4. If 0.5C charges passes through a wire in 10S, then what will be flowing through the wire? Step 1: Identify the given values. Charge Q = 0.5 C Time t = 10 s Step 2: Use the formula for current I = (Q)/(t). I = 0.5 C10 s Step 3: Calculate the current. I = 0.05 A The current flowing through the wire will be 0.05 A. 5. How many Watt-hours are there in 1000 joules? Step 1: Recall the conversion factor between Joules and Watt-hours. 1 Wh = 3600 J Step 2: Convert 1000 Joules to Watt-hours. Watt-hours = 1000 J3600 J/Wh Watt-hours ≈ 0.2778 Wh There are approximately 0.2778 Wh in 1000 joules. 6. What is the difference between a cell and a battery? A cell* is a single electrochemical unit that converts chemical energy into electrical energy. It has a single positive and a single negative terminal. A battery* is a collection of two or more cells connected together, typically in series, to provide a higher voltage or current capacity. 7. Which is more reliable floppy disk or a hard disk? A hard disk* is significantly more reliable than a floppy disk. Hard disks are enclosed in a sealed unit, protecting them from dust and physical damage, and use more robust magnetic media. Floppy disks are prone to damage from dust, magnetic fields, and physical wear due to their exposed, flexible nature. 8. What is e-mail? Write down its two advantages. E-mail (electronic mail)* is a method of exchanging digital messages from an author to one or more recipients over the internet or other computer networks. Two advantages of e-mail are: • Speed: Messages are delivered almost instantly across the globe. • Cost-effectiveness: It is generally free or very low-cost compared to traditional mail. Section I - Short Answer Questions (Third set): 1. What is meant by Critical angle? The critical angle* is the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90^. When the angle of incidence exceeds the critical angle, total internal reflection occurs. 2. What do you mean by Prism? A prism* is a transparent optical element with flat, polished surfaces that refract light. It is typically made of glass or plastic and has at least two non-parallel surfaces. Prisms are commonly used to disperse light into its constituent spectral colors or to reflect light. 3. Define reflection of light and draw a labeled ray diagram. Reflection of light* is the phenomenon where a light ray, upon striking a surface, bounces back into the same medium from which it originated. Ray Diagram for Reflection: ` Normal ^ | | / | / |/ i --+------------------ Mirror/Surface /|\ / | \ / | \ / | \ / | \ Incident Ray r Reflected Ray ` • The incident ray is the light ray striking the surface. • The reflected ray is the light ray bouncing off the surface. • The normal is a line perpendicular to the surface at the point of incidence. • The angle of incidence (i) is the angle between the incident ray and the normal. • The angle of reflection (r) is the angle between the reflected ray and the normal. • According to the law of reflection, the angle of incidence is equal to the angle of reflection (i=r).